This invention relates generally to global area communication systems and more particularly to wireless mobile communication systems.
As is known in the art, existing global communication systems enable a large number of subscribers to communicate and exchange a wide variety of information. The communication system includes a routing, or switching network. Typically, the network includes a plurality of communication paths interconnected at various nodes internal to the network. More particularly, the communication paths of the network include optical fiber, wired telephone links, and satellite links.
A switch is located at each network node, including nodes internal to the network as well as network input/output nodes at interfaces to, and from, the network. Information may be passed from a transmitting subscriber unit linked to a network input/output node to a receiving subscriber unit linked to another network input/output node by means of the switches at the network nodes. The information introduced to the network is formatted into the transmission protocol of the network. Routing through the network is typically under the control of a network management system (NMS). That is, each switch is controlled by the NMS to properly route the information through the network.
More particularly, in one such network, the information passes therethrough as digital information in a so-called asynchronous transfer mode (ATM) transmission protocol. Such a network is sometimes referred to as an ATM network. Thus, at each node is a multi-input/output port ATM switch. Each one of the switch ports has a unique address. Data coupled to one of the input/output port passes to another one of the input/output port in accordance with configuration of the switches in the network. The switch is configurable by control signals fed to the switch by the NMS. With such an ATM protocol, information is transmitted through the ATM network in packets of binary data. At each node, the packet includes a five byte header containing the address of the next "destination" node and forty-eight bytes of data. Thus, data passes from source node to destination node specified by the address portion of the packet. Packets travelling from the source node to destination node subsequently follow the unique path initialized by the network management system. In this way, the network management system addresses proper ones of the switches and provides such addressed switches with proper configurations to thereby properly route the information from the transmitting subscriber unit to the receiving subscriber unit.